Solving Misfires: A Guide to the 2006-2018 BMW 750i Ignition Coil
Eliminate engine misfires and restore the smooth, powerful performance of your BMW 750i's V8 engine.
- Ignition coil failure is very common on the 750i, especially on 2009+ models with the hot-running N63 engine.
- For the most reliable repair, replace all eight coils and spark plugs at the same time.
- Stick with high-quality, OEM-supplier brands like Bosch, Bremi, or Delphi to avoid premature failure.
- When replacing coils, always check for oil leaks from the valve cover gasket, as this is a primary cause of repeat failures.
Understanding Ignition Coil Failure in Your 750i
Ignition coil failure is a common issue on modern BMWs, and the 750i is no exception. The coils are located on top of the engine, where they are exposed to constant high heat and vibration, which causes them to wear out over time. This is especially true for the 2009 and newer models equipped with the N63 engine, which features a "hot-vee" design that places the extremely hot turbochargers in the valley of the engine, right next to the ignition coils. This intense heat is a major factor in premature coil failure.
A Common Cause of Repeat Failures: Oil Leaks
One of the most frequent reasons for ignition coil failure on the 750i is a leaking valve cover gasket. Oil can seep down into the spark plug tubes and soak the bottom of the ignition coil. This oil damages the coil's boot and wiring, leading to misfires and eventual failure. If you find oil in the spark plug wells when replacing a coil, you must also replace the valve cover gasket to prevent the new coil from failing again.
🎬 See how a leaking gasket ruins your ignition coils.Choosing the Right Aftermarket Ignition Coil
When replacing ignition coils, you have a choice between original BMW parts and aftermarket brands. For a critical component like this, quality matters. Sticking to brands that are known Original Equipment Manufacturers (OEM) for BMW is a smart choice. These companies produce the parts that BMW puts in their cars at the factory.
- Top Tier (OEM-Quality): Brands like Bosch, Delphi, and Bremi are often original equipment suppliers to BMW. Choosing one of these brands usually means you are getting a part of similar quality to the original without the dealership price tag. Hella and Denso are also highly reputable aftermarket brands known for meeting or exceeding OEM standards.
- Mid-Tier: Brands like Facet and Prenco may offer a lower price point, but there is less information available about their long-term reliability in high-heat BMW engines.
- Budget Brands: It is strongly recommended to avoid unbranded or budget-level coils. Forum discussions often point to a high risk of premature failure with cheaper parts, which can leave you stranded and doing the job all over again.
Pro Tip: Replace Coils and Plugs in Sets
If one ignition coil has failed, the others have been exposed to the same heat and wear and are likely near the end of their life. To ensure reliable performance and save on future labor, it is highly recommended to replace all eight ignition coils at the same time. This is also the perfect opportunity to replace your spark plugs, as worn plugs can strain the coils and cause them to fail prematurely.
Cost of Replacing Ignition Coils on a BMW 750i
| Part Type | Estimated Cost (Per Coil) |
|---|---|
| New OEM (Dealer) | $67 - $101 |
| New Aftermarket (OEM-Quality) | $36.57 - $83.66 |
| Shop Labor (All 8 Coils) | $75 - $180 |
Frequently Asked Questions (FAQ)
Can I replace just the one bad ignition coil?
You can, but it is not recommended. Coils wear out at a similar rate. Replacing only the failed one often means another one will fail soon, requiring you to do the job again. For best results, replace all eight at once.
How do I know for sure if my ignition coil is bad?
If your check engine light is on and you have a code for a specific cylinder misfire (e.g., P0304 for cylinder 4), you can perform a swap test. Move the suspected bad coil from cylinder 4 to another cylinder (like cylinder 1). Clear the codes and drive the car. If the code changes to P0301, you've confirmed the coil is the faulty part.
🎬 Learn more about diagnosing misfires and testing your coils.Is replacing ignition coils a difficult DIY job?
No, for most people with basic tools, this is a very DIY-friendly job. The coils are located on top of the engine and are easy to access after removing the plastic engine covers. The entire job for all eight coils can typically be done in under two hours.
🎬 Watch this step-by-step guide to replacing your 750i coils.Are there any recalls for BMW 750i ignition coils?
There are no specific recalls for ignition coils on the 2006-2018 BMW 750i, as they are considered a wear-and-tear item. However, BMW has issued Technical Service Bulletins (TSBs) like B121320 related to diagnosing misfires which can involve ignition coils. Always check for the latest TSBs or recalls with your VIN on the NHTSA website.
Helpful Videos
Technical Specifications
OEM Part Numbers: 12138616153 12135A06753 12138692611 12131748018 12139067830
This is a direct ignition, coil-on-plug design. Each of the 8 cylinders requires one coil. The coil transforms the vehicle's 12V power to over 40,000V to create a spark.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- BMW 750i:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Understanding Ignition Coil Failure in Your 750i
- A Common Cause of Repeat Failures: Oil Leaks
- Choosing the Right Aftermarket Ignition Coil
- Pro Tip: Replace Coils and Plugs in Sets
- Cost of Replacing Ignition Coils on a BMW 750i
- Frequently Asked Questions (FAQ)
- 🎟️ Get 5% Off